I picked the prada because I have one similar to that in the Saffiano leather and I LOVE it. Easily the best bag I've purchased for style and function.
Both are beautiful but as others have said although I prefer the shape and style of the Prada one, not loving the sheen on the leather it makes it look cheap.
I like the Givenchy! I have a Prada Saffiano too (Lux Tote) and that's part of the reason I love Prada, but am hesitant to pick up a different leather.
The color is even better in person and I'm loving the soft pebbled leather. I'm not a huge fan of the extra large zipper, but it can easily be tucked inside the bag. The handles have just enough of a drop to wear it over shoulder, but also make it feasible to carry in hand as well. Overall, I love it!